Project Summary Chronic kidney disease (CKD) is a health condition characterized by progressive decline in kidney function. Although children comprise only a small proportion of those with CKD, their kidney function declines more rapidly than adults, and they develop many extra-renal manifestations that impact health and complicate their management. As kidney function worsens, pediatric patients with CKD experience sleep disturbances (i.e., difficulties falling and staying asleep) and fatigue (i.e., experiences of feeling tired and the impact of those experiences on everyday life). Both types of symptoms are subjectively experienced and best assessed by obtaining information directly from patients. Such instruments are called patient-reported outcomes (PROs), which complement conventional clinical endpoints by examining patients? perspectives on their health experiences. Currently, there are no pediatric self-report instruments for children with CKD that focus on sleep disturbance or fatigue, two important gaps in the suite of outcome tools available to trialists who focus on interventions to mitigate the impact of CKD on pediatric patients. The proposed project will capitalize on existing data and provide additional evidence to support the qualification of the PROMIS Pediatric CKD Short Form ? Sleep Disturbance (COA #000119) and the PROMIS Pediatric CKD Short Form ? Fatigue (COA #000095) as clinical outcome assessments (COAs) to be used in clinical trials. The tools will fill the need for reliable and valid assessments of sleep disturbance and fatigue for children with CKD. The following specific aims will be completed: (1) Draft and submit a Qualification Plan for each proposed instrument, including information from prior qualitative research to support the content validity and comprehensibility of the PROs; (2) Conduct a prospective study of the PROs with children on dialysis to expand the proposed context of use to patients with more severe CKD; and, (3) Evaluate measurement properties of the instruments using cross- sectional and longitudinal analyses of PRO and clinical data collected from children with mild to severe CKD. The proposed approach is based on solid research design and psychometric analyses. The project will enable two COAs to move toward the final step in the qualification process. This work will support publicly available PROs that will provide valid, efficient assessments of sleep disturbance and fatigue in children with CKD, which is expected to increase the availability of effective drugs for this clinical population.